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Summary of Significant Accounting Policies - Additional Information (Detail) | 3 Months Ended
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Mar. 31, 2019 Country Segment
Significant Accounting Policies [Line Items] |
Number of reportable operating segments | Segment | 3
Number of commercial clean coal production facilities | 34
Number of countries in which the company has operations | 35
Number of countries in which the company does business through a network of correspondent brokers and consultants | 150

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- Definition Number of commercial clean coal production facilities. + References No definition available. + Details
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- Definition Number of Countries in which the Company does Business through a Network of Correspondent Brokers and Consultants + References No definition available. + Details
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- Definition Number of Countries in which the Company has Operations + References No definition available. + Details
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- Definition Significant Accounting Policies [Line Items] + References No definition available. + Details
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- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References No definition available. + Details
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